1. Field of the Invention
The present invention concerns a display device and a method of manufacturing the same and, more particularly, it relates to a self-light emitting display device in which light emitting elements such as organic EL elements are arranged on a substrate, and a method of manufacturing the same.
2. Description of the Related Art
A full color display device using light-emitting elements includes a constitution having a color filter in combination with a white light emitting element. One of the constitutions of the white light-emitting element is that a plurality of light-emitting layers are laminated in one light-emitting unit put between an anode and a cathode and they emit light simultaneously thereby taking-out white light. Further, the white light-emitting element also includes, as another constitution, a tandem structure in which a plurality of light-emitting units are laminated between a cathode and an anode.
However, in a case of laminating a plurality of light-emitting layers in one light-emitting unit, it is extremely difficult to control the light emission balance for RGB in the light-emitting unit. Then, the balance of light emission is controlled by supplying higher a current to a light-emitting element disposed to a display picture element for a color at the lowest light emitting efficiency than the current supplied to other light-emitting elements disposed to display picture elements for colors of good light emitting efficiency. However, this shortens the life of the light-emitting element of the display picture element for the color at the low light emitting efficiency compared with that of other display elements of display picture elements. Accordingly, this results in a difference to the degradation rate between each of the colors to cause off-balance for white color.
In order to solve the problem, it has been proposed to make the light emitting area of a display picture cell for a certain color, among display picture elements for various colors, different from the light-emitting area of the display picture element of other colors, thereby mitigating the off-balance of the white color caused by the difference of the light-emitting efficiency and the degradation rate between each of the self-light emitting elements (refer to JP-A No. 2001-290441).
Further, it has also been proposed a constitution of controlling the light emitting areas for RGB in a tandem type white light-emitting element in which light-emitting units for RGB are laminated by way of a connection layer (refer, for example, to JP-A No. 2004-79538).